zft Count Rumford's Account of a curious Phenomenon 
most interesting subject. If I have hitherto abstained from 
taking public notice of their observations on the opinion I have 
advanced on that subject, in my different publications, it was 
not from any want of respect for those gentlemen that I re- 
mained silent, but because I still found it to be quite impossible 
to explain the results of my own experiments, on any other 
principles than those which, on the most mature and dispas- 
sionate deliberation, I had been induced to adopt ; and because 
my own experiments appeared to me to be quite as conclusive 
(to say no more of them) as those which were opposed to them ; 
and, lastly, because I considered the principal point in dispute, 
relative to the passage of heat in fluids, as being so clearly 
established by the circumstances attending several great opera- 
tions of nature, that this evidence did not appear to me to be in 
danger of being invalidated by conclusions drawn from partial 
and imperfect experiments, and particularly from such as are 
allowed on all hands to be extremely delicate. 
In all our attempts to cause heat to descend in liquids, the 
heat unavoidably communicated to the sides of the containing 
vessel, must occasion great uncertainty with respect to the results 
of the experiment ; and, when that vessel is constructed of ice, 
the flowing down of the water resulting from the thawing of 
that ice, will cause motions in the liquid, and consequently in- 
accuracies of still greater moment, as I have found from my 
own experience; and, when thermometers immersed in a liquid, 
at a small distance below its surface, acquire heat, in consequence 
of a hot body being applied to the surface of the liquid, that 
event is no decisive proof that the heat acquired by the thermo- 
meter is communicated by the fluid, from above, downwards, 
from molecule to molecule, de proche en proche ; so far from 
